Generally, an electrical device can be suitably used for a liquid surface detecting device. For example, with reference to JP-2005-10047 A, the electrical device can be suitably used as a fixing member of the liquid surface detecting device. In this case, an up-down direction movement of a float which floats at a liquid surface is transmitted through an arm to a rotation member in which a magnet is fixed, so that the rotation member rotates. A Hall element, being a magnetoelectric conversion element, is arranged in the fixing member which rotatably holds the rotation member.
The fixing member (electrical device) of the liquid surface detecting device is molded by a resin material, with the Hall element (magnetoelectric conversion element) and terminals which are electrically connected with the Hall element being arranged at predetermined positions in the resin material to be insert-molded.
In this case, the end of the terminal is exposed to the outer side of the resin material to be connectable with an exterior electrical circuit, so that the Hall element can be electrically connected with the exterior circuit. A rubber material is arranged at a halfway (of longitudinal direction thereof) of the terminal, in such a manner that the rubber material covers the whole circumference of the terminal. The rubber material is also inert-molded in the resin material along with the above-described molding.
In this case, the fixing device of the liquid surface detecting device is arranged in a fuel tank and disposed at a position which is lower than the liquid surface position of a fuel in the fuel tank when the tank is filled up. Thus, the fixing member is completely dipped in the fuel in the case where the state of the fuel tank is between a full-tank state and a predetermined state (where liquid surface is at a predetermined position). Moreover, even when the liquid surface becomes lower than the fixing member, the fixing member will be dipped in the fuel and/or fuel spray will adhere to the fixing member because the liquid surface moves due to the vibration of the vehicle.
The terminal is made of a metal. However, because there is difference between a thermal coefficient of expansion of the metal and that of the resin material, a gap will occur between the terminal and the resin material in the use of the liquid surface detecting device. Thus, the fuel may intrude upon the gap to reach the Hall element. Therefore, the Hall element will be corroded and the normal operation thereof will be hampered.
In this case, the fixing member is provided with the rubber member which is positioned at the halfway (of longitudinal direction) of the terminal and covers the whole circumference of the terminal in the resin material. The rubber material is compressed to be deformed due to an injection pressure of the resin material in the insert-molding by the resin material. Thus, the bearing stress of a contact portion between the rubber material and the resin material increases due to the elastic force so that the sealing performance therebetween is improved, to restrict the fuel (having entered resin material) from reaching the Hall element.
However, according to the fixing device (electrical device) of the liquid surface detecting device, the force which elastically deforms the rubber material depends on the molding pressure of the resin material. Because there is a large variation in the molding pressure, it is difficult to stably maintain the sealing performance.